This patent document relates to techniques and optical devices that control or manipulate optical polarization of light.
Optical polarization, or state of polarization (SOP), is an important property of light that can impact or affect a wide range of optical and photonic devices. In optical communications, for example, as the bit rate per wavelength channel increases from 10 giga bit per second (Gbps) to 40 Gbps, 100 Gbps, and beyond, polarization issues become increasingly critical. In particular, the time-varying polarization mode dispersion (PMD), polarization dependent loss (PDL), and state of polarization (SOP) can cause the bitwidth to spread and signal level to fluctuate with time, and may increase the system's bit-error-rate (BER). Therefore, performance tests of an optical communication system against these polarization-related parameters PMD, PDL, and SOP can be desirable for assuring the healthy operation of high speed fiber optic communication systems. A polarization scrambling device for changing SOP at a controllable speed to reach all possible SOPs can be used to test the performance of the high speed fiber optic communication systems against rapid SOP variations.